Ultralow wear fluoropolymer composites: Nanoscale functionality from microscale fillers

A Review of Transfer Films and Their Role in Ultra-Low-Wear Sliding of Polymers

“…They found that running film hardness and modulus increase with increased sliding distance and decreased wear rates [24]. They suggested that changes in mechanical properties reflect filler accumulation and tribochemical degradation of PTFE, which is consistent with their more recent papers on the evolution of interface chemistry [27,29] and particle enrichment [30]. Ye [42] conducted similar measurements on transfer films from the same system.…”

Transfer film formation mechanism and tribochemistry evolution of a low-wear polyimide/mesoporous silica nanocomposite in dry sliding against bearing steel

“…9. This obervation was coincident with the detection of metal chelate salts of carboxylic acids in the case of PTFE/Al 2 O 3 composites sliding against steel [27,28]. The detection of carboxylate anion group demonstrated chemical mechanism responsible for the formation of robust transfer films, resulting in enhanced adhesion of the transfer films to the steel counterpart and the variation of sliding contact from polymer vs steel to polymer vs polymer.…”

“…Ye et al [26] carried out an in-situ observation of transfer film evolution based on an ultra-low wear polytetrafluoroethylene (PTFE)/Al 2 O 3 composite system, which indicated a complex interaction involving transfer film adhesion, tribochemistry, wear debris morphology and mechanical responses of polymer matrices. Subsequent studies on this ultra-low wear system further revealed dominant role of mechanochemistry and nanoscale functionality from microscale Al 2 O 3 fillers on the formation of robust transfer film and the ultra-low wear of this material system [27][28]. Bahadur and Sunkara [29] quantitatively measured the bonding strengths between polyphenylene sulfide (PPS) nanocomposite transfer film and steel substrate.…”

High-performance PTFE nanocomposites based on halloysite nanotubes

“…As for pure PTFE, the obvious banding tears can be distinguished due to the sliding behaviour between polymer and steel. This phenomenon proves the poor wear resistance of PTFE because of the weak Van der Waals forces between the PTFE modules (Lee et al, 2007;Krick et al, 2015). As shown in Fig.…”

“…When the addition of alumina nanoparticles was at 5 wt.%, the wear rate was reduced drastically to ∼10-7 mm 3 /Nm, 1000 times less than that of pure PTFE. Krick et al (2015) reported that the nanostructured alumina microfiller-filled PTFE exhibited an extraordinary wear resistance at a small filling amount of alumina (<5 wt.%) and the wear rate of the PTFE composites reduced by more than four orders of magnitude. Chen et al (2003) studied the tribological behaviour of CNTs-filled PTFE composites and the results showed that the wear rate of the CNTs/PTFE composite with 20 vol.% CNT filling was only 1/290 that of pure PTFE.…”